We are endeavoring to determine the biological role of secondary natural products (alkaloids, terpenes, non-protein amino acids) which are found in higher plants. For example, nicotine, which is found in tobacco, is being studied in the hope that its function in tobacco will be discovered. This is being done by administering to tobacco labelled nicotine and then examining the tobacco for metabolites of the alkaloid. Other alkaloids which are being examined in a similar way are: atropine, gramine, coniine, and anabasine.